HELP What is the geometric mean of 3 and 7?

Which of the following is most likely the next step in the series? a3z, b6y, c9x, d12w, е15v, f18u

The boiling point of water at an elevation of 0 feet is 212 degrees fahrenheit (°f). for every 1,000 feet of increase in elevation, the boiling point of water decreases by about 2°f. which of the following represents this relationship if b is the boiling point of water at an elevation of e thousand feet? a) e = 2b - 212 b) b = 2e - 212 c) e = -2b + 212 d) b = -2e + 212

Julie was able to walk 16 km through the zoo in 6 hours. how long will it take her to walk 24 km through the zoo?